Mobile communications systems such as 2nd generation (2G; for example GSM), 3rd generation (3G; for example UMTS) use well-defined smart cards in addition to mobile devices. In UMTS, the smart card is called UICC (Universal Integrated Circuits Card).
A modern smart card like the UICC can offer a number of services to the host like the phone; for example it can, very naturally, offer the service of a smart card according the smart card device class. For instance, UICCs providing USB interchip interface may allow transfer of Subscriber Identity Module (SIM) Application Protocol Data Units (APDUs) by means of using smart card class.
In architectures of mobile devices, different engines have to access the UICC. For instance, in a mobile terminal a converged architecture may comprise a modem engine configured to perform phone functions and at least one further application engine for further function.